<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>弹性布局</title>
    <style>
    * {
        margin: 0;
        padding: 0;
    }
    .box{
        display: flex;
       /*  display:inline-block; /* 行内块级元素 */ 
        background-color: red;
        height: 100px;
        width: 50%;
        margin-bottom: 10px;
    }

    .box:nth-child(2) {
        background-color: blue;
    }
    .item {
        flex:1;
        font-size: 20px;
        color:black;
        display: inline-block;
        width: 33.33%;
    }
    .item:nth-child(odd){
        background: yellow;
    }

    </style>
</head>
<body>
<div class="box">
    <div class="item">1</div><div class="item">2</div><div class="item">3</div>
</div><div class="box"></div>
</body>
</html>